Mexico’s tiny tequila splitfin fish was once a common inhabitant in the country’s Teuchitlán river in the western part of the country. But due to the combined effects of water pollution, invasive fish species, and over-extraction of water resources, the small fish became extinct in the wild. The fish’s fate, however, took a turn for the better thanks to a conservation effort that successfully reintroduced the species to its native habitat.
The conservation project started more than two decades ago, when conservationists from the Chester Zoo in England and other European institutions arrived in Teuchitlán, a town near the Tequila volcano, to help set up a laboratory for conserving Mexican fish. The effort included several pairs of the tequila splitfin fish, also called zoogoneticus tequila, that they picked up from the aquariums of collectors, said conservationist Omar Domínguez, who played a key role in the project.
The fish first started reproducing in aquariums and within a few years, the researchers started exploring how to safely reintroduce the species to the Teuchitlán river. Since returning the fish right back into the river was considered too dangerous for their survival, the scientists created an artificial pond for a semi-captivity stage. In 2012, they introduced 40 pairs of tequila fish there.
Just two years later, there were some 10,000 fish swimming in the pond — a big enough number to attract funding from multiple international organizations to move the experiment to the river. As such, the conservationists began studying the river’s environment, looking at parasites, microorganisms in the water, the interaction with predators, competition with other fish, and then introduced the fish in floating cages, inside of which they rapidly multiplied.
The fish were then marked so they could be tracked and set free. Just six months after being actually released into the river, the fish’s population grew by 55 percent, and just last month, the conservationists noticed that the species also expanded to another part of the river.
“The project has been cited as an International Union for the Conservation of Nature (IUCN) case study for successful global reintroductions – with recent scientific studies confirming the fish are thriving and already breeding in the river,” the Chester Zoo said in a statement.
The reintroduction of species back into their natural habitat is a complex and time-consuming process, which is why this particular case is a major win for conservation efforts and the world’s biodiversity.